/drivers/media/video/v4l2-fh.c
C | 126 lines | 81 code | 18 blank | 27 comment | 13 complexity | edb3701b3ce0d07072f03382a93809e4 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
1/* 2 * v4l2-fh.c 3 * 4 * V4L2 file handles. 5 * 6 * Copyright (C) 2009--2010 Nokia Corporation. 7 * 8 * Contact: Sakari Ailus <sakari.ailus@maxwell.research.nokia.com> 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * version 2 as published by the Free Software Foundation. 13 * 14 * This program is distributed in the hope that it will be useful, but 15 * WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 * General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program; if not, write to the Free Software 21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 22 * 02110-1301 USA 23 */ 24 25#include <linux/bitops.h> 26#include <linux/slab.h> 27#include <media/v4l2-dev.h> 28#include <media/v4l2-fh.h> 29#include <media/v4l2-event.h> 30#include <media/v4l2-ioctl.h> 31 32int v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev) 33{ 34 fh->vdev = vdev; 35 INIT_LIST_HEAD(&fh->list); 36 set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags); 37 fh->prio = V4L2_PRIORITY_UNSET; 38 39 /* 40 * fh->events only needs to be initialized if the driver 41 * supports the VIDIOC_SUBSCRIBE_EVENT ioctl. 42 */ 43 if (vdev->ioctl_ops && vdev->ioctl_ops->vidioc_subscribe_event) 44 return v4l2_event_init(fh); 45 46 fh->events = NULL; 47 48 return 0; 49} 50EXPORT_SYMBOL_GPL(v4l2_fh_init); 51 52void v4l2_fh_add(struct v4l2_fh *fh) 53{ 54 unsigned long flags; 55 56 if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags)) 57 v4l2_prio_open(fh->vdev->prio, &fh->prio); 58 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 59 list_add(&fh->list, &fh->vdev->fh_list); 60 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 61} 62EXPORT_SYMBOL_GPL(v4l2_fh_add); 63 64int v4l2_fh_open(struct file *filp) 65{ 66 struct video_device *vdev = video_devdata(filp); 67 struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL); 68 69 filp->private_data = fh; 70 if (fh == NULL) 71 return -ENOMEM; 72 v4l2_fh_init(fh, vdev); 73 v4l2_fh_add(fh); 74 return 0; 75} 76EXPORT_SYMBOL_GPL(v4l2_fh_open); 77 78void v4l2_fh_del(struct v4l2_fh *fh) 79{ 80 unsigned long flags; 81 82 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 83 list_del_init(&fh->list); 84 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 85 if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags)) 86 v4l2_prio_close(fh->vdev->prio, fh->prio); 87} 88EXPORT_SYMBOL_GPL(v4l2_fh_del); 89 90void v4l2_fh_exit(struct v4l2_fh *fh) 91{ 92 if (fh->vdev == NULL) 93 return; 94 95 fh->vdev = NULL; 96 97 v4l2_event_free(fh); 98} 99EXPORT_SYMBOL_GPL(v4l2_fh_exit); 100 101int v4l2_fh_release(struct file *filp) 102{ 103 struct v4l2_fh *fh = filp->private_data; 104 105 if (fh) { 106 v4l2_fh_del(fh); 107 v4l2_fh_exit(fh); 108 kfree(fh); 109 } 110 return 0; 111} 112EXPORT_SYMBOL_GPL(v4l2_fh_release); 113 114int v4l2_fh_is_singular(struct v4l2_fh *fh) 115{ 116 unsigned long flags; 117 int is_singular; 118 119 if (fh == NULL || fh->vdev == NULL) 120 return 0; 121 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 122 is_singular = list_is_singular(&fh->list); 123 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 124 return is_singular; 125} 126EXPORT_SYMBOL_GPL(v4l2_fh_is_singular);